Abstract
A series of glass-ceramics were prepared by heat-treatments of 40Na2O-30MoO3-30P2O5 (in mol%) glass in a temperature range from 380 (Tg) to 490 °C (Tc) and for 1–24 h. The prepared glass-ceramics contain from 2 to 25 wt.% of crystalline NaMoO2PO4. The sodium-ion conductivity in these materials decreases up to one order of magnitude with an increase in the degree of crystallization due to the immobilization of sodium ions in crystalline NaMoO2PO4. The transport of sodium ions in these materials occurs primarily through the dominant continuous glassy phase, and it is weakly affected by the sporadically distributed crystalline grains. However, the prepared glass-ceramics exhibit high proton conductivity in a humid atmosphere and remarkable humidity-sensing properties; this could be related to crystalline NaMoO2PO4, which provides sites for water adsorption. The glass-ceramic prepared at 450 °C for 24 h shows the best humidity-sensing performance among all samples, showing an increase in proton conductivity for more than seven orders of magnitude with the increase in relative humidity from 0% to 95%. Under a highly humid atmosphere (95% relative humidity and 25 °C), the proton conductivity of this glass-ceramic reaches 5.2 × 10−3 (Ω cm)−1. Moreover, the electrical response of these materials on the change in the relative humidity is linear and reversible in the entire range of the relative humidity, which indicates that they are novel promising candidates for application as humidity sensors.
Highlights
Publisher’s Note: MDPI stays neutralThe controlled crystallization of glasses is an advantageous procedure for the preparation of glass-ceramics with specific physicochemical properties [1,2]
Crystallization resulted in a moderate decrease in sodium-ion conductivity with an increase in the amount of crystalline Na(MoO2 )PO4, we show that prepared glass-ceramics exhibit very high sensitivity to humidity, which indicates their promising application as humidity sensors
The temperatures of the heat-treatments of the 40Na2 O-30MoO3 -30P2 O5 glass were selected based on the reported DSC results [26]: 380 ◦ C, 450 ◦ C and 490 ◦ C
Summary
Publisher’s Note: MDPI stays neutralThe controlled crystallization of glasses is an advantageous procedure for the preparation of glass-ceramics with specific physicochemical properties [1,2]. According to the recently updated definition, glass-ceramics are “inorganic, non-metallic materials prepared by controlled crystallization of glasses which contain at least one type of functional crystalline phase and a residual glassy phase” [1]. In these materials, the volume fraction of the crystalline phase may vary from ppm to almost 100% [1]. This, in turn, provides possibilities to increase mechanical toughness, tailor conductive pathways for ions and electrons and to form a template or framework for subsequent interaction with other materials [2] All these valuable properties make glass-ceramics highly important for application in various areas, from medicine and denwith regard to jurisdictional claims in published maps and institutional affiliations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
